/Engine/Plugins/Animation/IKRig/Source/IKRig/Public/Rig/Solvers/IKRigSolver.h
This is the base class for creating your own solver type that integrates into the IK Rig framework/editor.
[UCLASS](Programming/UnrealArchitecture/Reference/Classes#classdeclaration)(Abstract, HideCategories=UObject) class UIKRigSolver : public [UObject](API\Runtime\CoreUObject\UObject\UObject)